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Solar photospheric magnetic reconnection
Earth, Planets and Space volume 53, pages605–609(2001)
We investigate photospheric magnetic reconnection due to an encounter of oppositely directed vertical magnetic flux sheets, performing 2.5-dimensional magnetohydrodynamic (MHD) numerical simulations. We construct the initial flux sheets adopting the thin flux tube approximation. Since actual solar resistivity possesses a maximum at the temperature-minimum region, we adopt a resistivity model in which the resistivity is described as a function of height with a maximum (where the magnetic Reynolds number = 1000) at a middle height of our simulation box. Owing to the resistivity, the Sweet-Parker type reconnection occurs at the middle. The inflow speed (υ i ∼ 160 m/s) is nearly equal to the speeds implied by observations of canceling magnetic features on the photosphere. Thus photospheric reconnection seems to be a cancellation mechanism. It is shown that upward propagating MHD slow mode waves are generated by an upward reconnection jet. Moreover, when we incline the initial field lines 30° from the vertical direction in the other flux sheet, Alfvén waves are also generated as a result of the reconnection. The energy flux carried by the slow modes and Alfvén waves are 1010 and 108 erg/cm2/s, respectively, and the durations are 40 s. Since in models of solar spicules upward propagating slow waves or Alfvén waves are usually assumed as the initial perturbations, we compare the energy of both waves. It is found that the wave energies due to the reconnection are comparable to those assumed in spicule models. Thus the photospheric magnetic reconnection might be one of the causes of solar spicules.
Garcia de la Rosa, J. I., M. A. Aballe, and M. Collados, An example of the cancellation of magnetic fields during the decay of an active region, Sol. Phys., 124, 219–226, 1989.
Hollweg, J. V., On the origin of solar spicules, ApJ, 257, 345–353, 1982.
Hollweg, J. V., Alfvénically driven slow shocks in the solar chromosphere and corona, ApJ, 389, 731–738, 1992.
Hollweg, J. V, S. Jackson, and D. Galloway, Alfvén waves in the solar atmosphere III. Nonlinear waves on open flux tubes, Sol. Phys., 75, 35–61, 1982.
Kovitya, P. and L. Cram, Electrical conductivity in sunspots and the quiet photosphere, Sol. Phys., 84, 45–48, 1983.
Kudoh, T. and K. Shibata, Alfven wave model of spicules and coronal heating, ApJ, 514, 493–505, 1999.
Litvinenko, K., Photospheric magnetic reconnection and canceling magnetic features on the Sun, ApJ, 515, 435–440, 1999.
Parker, E. N., The solar-flare phenomenon and the theory of reconnection and annihilation of magnetic fields, ApJS, 8, 177–211, 1963.
Richtmyer, R. D. and K. W. Morton, Difference Method for Initial Value Problem, 2nd ed., 401 pp., Interscience Publishers, New York, 1967.
Roberts, B. and A. R. Webb, Vertical motions in an intense magnetic flux tube, Sol. Phys., 56, 5–35, 1978.
Rubin, E. L. and S. Z. Burstein, Difference methods for the inviscid and viscous equations of a compressible gas, J. Comp. Phys., 2, 178–196, 1967.
Schrijver, C. J., A. M. Title, A. A. van Ballegooijen, and R. A. Shine, Sustaining the quiet photospheric network: The balance of flux emergence, fragmentation, merging, and cancellation, ApJ, 487, 424–436, 1997.
Schrijver, C. J., A. M. Title, K. L. Harvey, N. R. Sheeley, Jr., Y.-M. Wang, G. H. J. van den Oord, R. A. Shine, T. D. Tarbell, and N. E. Hurlburt, Large-scale coronal heating by the small-scale magnetic field of the Sun, Nature, 394, 152–154, 1998.
Solanki, S. K., Small scale solar magnetic fields: An overview, Space Sci. Rev., 61, 1–188, 1993.
Sterling, A. C. and J. T. Mariska, Numerical simulations of the rebund shock model for solar spicules, ApJ, 349, 647–655, 1990.
Sturrock, P. A., Chromospheric magnetic reconnection and its possible relationship to coronal heating, ApJ, 521, 451–459, 1999.
Suematsu, Y., K. Shibata, T. Nishikawa, and R. Kitai, Numerical hydrodynamics of the jet phenomena in the solar atmosphere I. Spicules, Sol. Phys., 75, 99–118, 1982.
Sweet, P. A., The neutral point theory of solar flares, in IAU Symp. 6, Electromagnetic Phenomena in Cosmical Physics, edited by B. Lehnert, pp. 123–134, Cambridge Univ. Press, Cambridge, 1958.
Takeuchi, A. and K. Shibata, Magnetic reconnection induced by convective intensification of solar photospheric magnetic fields, ApJL, 546, L73–L76, 2001.
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Takeuchi, A., Shibata, K. Solar photospheric magnetic reconnection. Earth Planet Sp 53, 605–609 (2001). https://doi.org/10.1186/BF03353278
- Current Sheet
- Slow Wave
- Magnetic Reconnection
- Magnetic Reynolds Number
- Coronal Heating